1. Field of the Invention
This invention relates broadly to an agent usable as an extinguishant, a method of preparing the fire extinguishing agent, and several uses of the fire extinguishing agent.
2. State of the Art
It is well known that halogenated hydrocarbons, or halons, are very effective fire extinguishing agents. Halon 1301 (CF.sub.3 Br) has been in widespread use for "total flood" applications; that is, applications in which the agent is stored and discharged into occupied spaces such as computer facilities and restaurant kitchens, often by an automatic discharge or sprinkler system. Halon 1211 (CF.sub.2 ClBr) has slightly greater toxicity but, due to its effectiveness, is extensively used for hand-held tank and outdoor mobile "streaming" applications, particularly for jet fuel fires. Halon 1211 and Halon 1301 have also been mixed together to provide a multipurpose extinguishing agent.
The halons operate as fire extinguishants by a complex chemical reaction involving the disruption of free-radical chain reactions to effectively remove oxygen from the fire and extinguish a fire. In addition, the halons are clean as well as effective, because they leave no residue and because they do not damage equipment or facilities to which they are applied.
However, the halons have several limitations. First, it has been determined that the halons have an ozone depleting effect. The halons break down into chlorofluorocarbon components which react with and thereby remove ozone from the atmosphere. Therefore, there has recently been a push away from halons and toward finding alternatives which are as effective. However, although a large amount of research has been conducted to find a replacement, none of the candidates has proven to be as effective as halons, and at the same time harmless to the environment.
Second, due to the complex chemical reaction which occurs during extinguishment, the halons operate best in either a closed space, where there is a contained oxygen supply, or in very close proximity to the fire. They are not as effective in outdoor use where the oxygen supply surrounding the fire is abundant, particularly when sprayed from large distances toward a fire. Therefore, they are not particularly effective in extinguishing fires when sprayed at a distance from the flames.
Third, even the halons do not provide as effective an extinguishment as desired. For example, while the halons extinguish the flames of a fire, they do not permit timely re-entry of a previously burning building or timely handling of a previously burning object due to the remaining heat. Moreover, the halons do not prevent reignition of a fire at the location of a previously extinguished fire.